The present invention is related to the field of carton forming mechanisms and more particularly to a mechanism adapted to fold corner flaps of a rectangular pre-cut carton blank over onto the blank body thereby laminating portions of the blank body.
It is not essentially new to provide a mechanism whereby pre-cut flaps are folded over onto a carton blank body to provide a double thickness lamination at a strategic location within the carton form to assure structural rigidity. However, such machines have previously performed this function at a station very near to the hopper in which the carton blanks are received and independently dispensed in response to the operation of an appropriate escapement mechanism. It is not unusual for the hopper to be located directly over a forming mandril whereby the corner flaps are partially folded upwardly as the carton blank is drawn from the hopper. Such mandrils serve their purpose, but necessarily interrupt the flow of carton forms through the machine and therefore considerably slow the production rate of the machine. It is therefore desirable to provide some form of flap laminating mechanism that will operate on a carton blank as it is moved from the hopper to a carton forming station, without interrupting or halting movement of the carton at any point along its path from the hopper to the forming station.
The present invention was conceived to perform the flap laminating operations as the individual cartons are moved continuously from the hopper to a forming station without interrupting or halting at any time the forward progress of the carton blanks. This is essentially accomplished in a two-step laminating procedure whereby glue is first applied to the carton blank adjacent the flap areas and a transversely spaced pair of pivot arms are swung upwardly against the flaps pivoting them up to an approximate 90 degree angle to the remainder of the associated carton blank. The arms hold the flaps in this position as the blanks continue to move toward the forming station until forward edges thereof engage flap folding irons. As soon as the flaps engage these irons, the folding arms are pivoted back downwardly out of the way of the approaching remainder of the carton blank. The irons function to fold the flaps downwardly and inwardly against the carton blank body and glue layers. Again, this is accomplished as the individual carton blanks move continuously toward the carton forming station.